When run stress tests with RXE, the following Call Traces often occur
watchdog: BUG: soft lockup - CPU#2 stuck for 22s! [swapper/2:0]
...
Call Trace:
<IRQ>
create_object+0x3f/0x3b0
kmem_cache_alloc_node_trace+0x129/0x2d0
__kmalloc_reserve.isra.52+0x2e/0x80
__alloc_skb+0x83/0x270
rxe_init_packet+0x99/0x150 [rdma_rxe]
rxe_requester+0x34e/0x11a0 [rdma_rxe]
rxe_do_task+0x85/0xf0 [rdma_rxe]
tasklet_action_common.isra.21+0xeb/0x100
__do_softirq+0xd0/0x298
irq_exit+0xc5/0xd0
smp_apic_timer_interrupt+0x68/0x120
apic_timer_interrupt+0xf/0x20
</IRQ>
...
The root cause is that tasklet is actually a softirq. In a tasklet
handler, another softirq handler is triggered. Usually these softirq
handlers run on the same cpu core. So this will cause "soft lockup Bug".
Fixes: 8700e3e7c4 ("Soft RoCE driver")
Link: https://lore.kernel.org/r/20200212072635.682689-8-leon@kernel.org
Signed-off-by: Zhu Yanjun <yanjunz@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
8ac0e6641c